<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
<form action="#" method="post">
{{ form_label(form) }}
            {{ form_widget(form, { 'attr' : { 'class' : 'form-horizontal' } }) }}
            {{ form_errors(form) }}
    <input type="submit" name="submit" />
</form>